摘要：
*@paramargs*/publicstaticvoidmain（String[]args）｛for（int i=0；i++）｛System.out.println（“[”+i+“]”+“the verificationcodes]”+createVerificationCode（6））作为调用和测试验证代码生成方法的入口；
前言：以前做过的一个项目，刚开的时候始验证码是在前端生成前端验证的，后来觉得不靠谱，另外就是找回密码的功能也需要发送邮件和短信的验证码，所以，验证码就必须在后端生成并且保存到应用会话中才行了！所以，就有了下面的这段简单的代码，这段代码虽然简单，但也是生成验证码的一种思路，在此小记一笔以备后用。
1：如下是生成验证码、测试生成验证码的方法，比较简单，注释也比较清楚，不多说了
package start; import java.util.Random; public class HelloMain { /** * 主函数，作为调用和测试生成验证码方法的入口 * @param args */ public static void main(String[] args) { for(int i=0; i<10;i++) { System.out.println("【"+i+"】"+" 【the verification code is】 "+createVerificationCode(6)); } } /** * 生成指定长度的验证码 * @author Q * @param verificationCodeLength * @return String * @since 2016-09-6 */ public static final String createVerificationCode(int verificationCodeLength) { // 所有候选组成验证码的字符，可以用中文 String[] verificationCodeArrary={"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z", "A","B","C","D","E","F","G","H","I","J", "K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z" }; String verificationCode = ""; Random random = new Random(); //此处是生成验证码的核心了，利用一定范围内的随机数做为验证码数组的下标，循环组成我们需要长度的验证码，做为页面输入验证、邮件、短信验证码验证都行 for(int i=0;i<verificationCodeLength;i++){verificationCode += verificationCodeArrary[random.nextInt(verificationCodeArrary.length)];} return verificationCode; } }
2：如下是运行主函数生十组六位长度验证码的运行结果演示图
3：小结
此例的核心和JS-改变页面的颜色之变化核心-获取六位的随机数类似，都需要利用随机数函数来模拟生成六位随机数经过处理一下后，前者作为验证码后者作为颜色的十六进制六位表示值。